TETREUTREPTIA POMQUETENSIS (EUGLENOPHYTA), A PSYCHROPHILIC SPECIES: GROWTH AND FATTY ACID COMPOSITION |
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Authors: | J L McLachlan J M Curtis K Boutilier M Keusgen M R Seguel |
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Institution: | Department of Biology, Dalhousie University, Halifax, Nova Scotia B3H 4J1, Canada; National Research Council, 1411 Oxford St., Halifax, Nova Scotia B3H 3Z1, Canada; Institut für Pharmazeutische Biologie, Univerität Bonn, Nußallee 6, D-53115, Bonn, Germany; Department of Biology, Acadia University, Wolfville, Nova Scotia B0P 1X0, Canada |
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Abstract: | Tetreutreptia pomquetensis McLachlan, Fritz et Seguel, a quadriflagellated euglenoid isolated from a shallow-water embayment of the southeastern Gulf of St. Lawrence, is a common winter species where habitats are ice covered for 4 to 5 months. Growth in culture, which was similar to that of many euryhaline species, was limited at normal seawater salinities to temperatures between ∼0° and 7° C, and the alga could not be maintained at 10° C; thus, it is a strict psychrophile. The maximum growth rate (μ≅ 0.35·days−1) was around 5° C and, given its size (∼100 μm length), high productivities are indicated. The major fatty acids (FAs) identified were 18:4ω3, 16:4ω3, 20:5ω3, and 16:0. The overall FA spectrum does not align closely to other euglenoids but may reflect more the low growth temperature. The presence of 18:5ω3 is unusual, as this FA had been known previously only from dinoflagellates and haptophytes. The two most abundant sulfoquinovosyl diacylglycerols (SQDGs) had pairings of 18:4/16:0] and 18:4/18:4] and together constituted 80% of the total SQDGs. The latter pairing is unique, not having been previously recognized. The FA data support the hypothesis that the degree of unsaturation is indicative of low temperatures and membrane integrity. |
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Keywords: | euglenoid fatty acids growth psychrophiles sulfolipids temperature Tetreutreptia pomquetensis |
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